Method and system using driver equalization in transmission line channels with power or ground terminations

ABSTRACT

A driver circuit device using driver equalization in power and ground terminated transmission line channels. The driver circuit device can include a weaker pull-up driver, which is needed to pre-emphasize the pull-up signal for driver equalization in power terminated transmission line channels. The driver circuit device can also include a weaker pull-down driver, which is needed to pre-emphasize the pull-down signal for driver equalization in ground terminated transmission line channels. In the transmission line channels with power terminations, a weaker pull-up Ron is implemented. In the transmission line channels with ground terminations, a weaker pull-down Ron is implemented. Drivers implemented in power and/or ground terminated transmission line channels can be used to improve device performance, such as in signal eye opening.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/061,957, filed on Mar. 4, 2016, the contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to communication systems and integratedcircuit (IC) devices. More particularly, the present invention providesa driver circuit device using driver equalization in transmission linechannels with power or ground terminations.

Over the last few decades, the use of communication networks hasexploded. In the early days of the Internet, popular applications werelimited to emails, bulletin board, and mostly informational andtext-based web page surfing, and the amount of data transferred wasusually relatively small. Today, Internet and mobile applications demanda huge amount of bandwidth for transferring photo, video, music, andother multimedia files. For example, a social network like Facebookprocesses more than 500 TB of data daily. With such high demands on dataand data transfer, existing data communication systems need to beimproved to address these needs.

CMOS technology is commonly used to design communication systemsimplementing Optical Fiber Links. As CMOS technology is scaled down tomake circuits and systems run at higher speed and occupy smaller chip(die) area, the operating supply voltage is reduced for lower power.Conventional FET transistors in deep-submicron CMOS processes have verylow breakdown voltage as a result the operating supply voltage ismaintained around 1 Volt. However, the Optical Modulators used in100G-class optical links often require a bias voltage of more than 2Volts across the anode and cathode nodes of the modulator for effectiveoptical amplitude and/or phase modulation. These limitations providesignificant challenges to the continued improvement of communicationsystems scaling and performance.

Accordingly, improvements to driver equalization in integrated circuitdevices are highly desirable.

BRIEF SUMMARY OF THE INVENTION

The present invention relates to communication systems and integratedcircuit (IC) devices. More particularly, the present invention providesa driver circuit device using driver equalization in transmission linechannels with power or ground terminations.

In an embodiment, the present invention provides a driver circuit deviceusing driver equalization in power and ground terminated transmissionline channels. The driver circuit device can include a weaker pull-updriver, which is needed to pre-emphasize the pull-up signal for driverequalization in power terminated transmission line channels. The drivercircuit device can also include a weaker pull-down driver, which isneeded to pre-emphasize the pull-down signal for driver equalization inground terminated transmission line channels. In the transmission linechannels with power terminations, a weaker pull-up Ron is implemented.In the transmission line channels with ground terminations, a weakerpull-down Ron is implemented. Drivers implemented in power and/or groundterminated transmission line channels can be used to improve deviceperformance, such as in signal eye opening.

Many benefits are recognized through various embodiments of the presentinvention. Such benefits include improvement of device performance byincreasing signal eye opening. Other benefits will be recognized bythose of ordinary skill in the art that the mechanisms described can beapplied to other communications systems as well.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C are simplified circuit diagrams illustrating driver circuitdevices according to various embodiments of the present invention.

FIGS. 2A-2D are simplified circuit diagrams illustrating driver circuitdevices according to conventional embodiments.

FIGS. 3A-3D are simplified circuit diagrams illustrating driver circuitdevices according to various embodiments of the present invention.

FIG. 4 is a simplified graph illustrating an impulse response at areceiver input of a driver circuit device according to an embodiment ofthe present invention.

FIG. 5A is a simplified graph illustrating an eye diagram of a drivercircuit device according to a conventional embodiment.

FIG. 5B is a simplified graph illustrating an eye diagram of a drivercircuit device according to an embodiment of the present invention.

FIGS. 6A and 6B are simplified graphs illustrating a signal outputs fora driver circuit device according to various embodiments of the presentinvention.

FIG. 7 is a simplified circuit diagram illustrating a driver circuitdevice according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to communication systems and integratedcircuit (IC) devices. More particularly, the present invention providesa driver circuit device using driver equalization in transmission linechannels with power or ground terminations.

The following description is presented to enable one of ordinary skillin the art to make and use the invention and to incorporate it in thecontext of particular applications. Various modifications, as well as avariety of uses in different applications will be readily apparent tothose skilled in the art, and the general principles defined herein maybe applied to a wide range of embodiments. Thus, the present inventionis not intended to be limited to the embodiments presented, but is to beaccorded the widest scope consistent with the principles and novelfeatures disclosed herein.

In the following detailed description, numerous specific details are setforth in order to provide a more thorough understanding of the presentinvention. However, it will be apparent to one skilled in the art thatthe present invention may be practiced without necessarily being limitedto these specific details. In other instances, well-known structures anddevices are shown in block diagram form, rather than in detail, in orderto avoid obscuring the present invention.

The reader's attention is directed to all papers and documents which arefiled concurrently with this specification and which are open to publicinspection with this specification, and the contents of all such papersand documents are incorporated herein by reference. All the featuresdisclosed in this specification, (including any accompanying claims,abstract, and drawings) may be replaced by alternative features servingthe same, equivalent or similar purpose, unless expressly statedotherwise. Thus, unless expressly stated otherwise, each featuredisclosed is one example only of a generic series of equivalent orsimilar features.

Furthermore, any element in a claim that does not explicitly state“means for” performing a specified function, or “step for” performing aspecific function, is not to be interpreted as a “means” or “step”clause as specified in 35 U.S.C. Section 112, Paragraph 6. Inparticular, the use of “step of” or “act of” in the Claims herein is notintended to invoke the provisions of 35 U.S.C. 112, Paragraph 6.

Please note, if used, the labels left, right, front, back, top, bottom,forward, reverse, clockwise and counter clockwise have been used forconvenience purposes only and are not intended to imply any particularfixed direction. Instead, they are used to reflect relative locationsand/or directions between various portions of an object.

FIG. 1A is a simplified circuit diagram illustrating a driver circuitdevice according to various embodiments of the present invention. Asshown, driver circuit 101 includes at least a driver 110, a transmissionline channel 120, and a receiver 130. The driver 110 can include adriver input and a driver output. The transmission line channel 120 caninclude a first end and a second end. This transmission line channel canbe a configured as point-to-point or multi-stub. The receiver 130 caninclude a receiver input and a receiver output. The first end of thetransmission line channel 120 can be electrically coupled to the driveroutput. The second end of the transmission line channel 120 can beelectrically coupled to the receiver input. This second end is alsoconfigured with a center-tapped termination 141 having both a powertermination to VDD and a ground termination to GND.

FIG. 1B is a simplified circuit diagram illustrating a driver circuitdevice according to various embodiments of the present invention. Asshown, driver circuit 102 includes at least a driver 110, a transmissionline channel 120, and a receiver 130. The driver 110 can include adriver input and a driver output. The transmission line channel 120 caninclude a first end and a second end. This transmission line channel canbe a configured as point-to-point or multi-stub. The receiver caninclude a receiver input and a receiver output. The first end of thetransmission line channel 120 can be electrically coupled to the driveroutput. The second end of the transmission line channel 120 can beelectrically coupled to the receiver input. This second end isconfigured only with a power termination 142 to VDD.

FIG. 1C is a simplified circuit diagram illustrating a driver circuitdevice according to various embodiments of the present invention. Asshown, driver circuit 103 includes at least a driver 110, a transmissionline channel 120, and a receiver 130. The driver 110 can include adriver input and a driver output. The transmission line channel 120 caninclude a first end and a second end. This transmission line channel canbe a configured as point-to-point or multi-stub. The receiver caninclude a receiver input and a receiver output. The first end of thetransmission line channel 120 can be electrically coupled to the driveroutput. The second end of the transmission line channel 120 can beelectrically coupled to the receiver input. This second end is alsoconfigured only with a ground termination to GND.

FIG. 2A is a simplified circuit diagram illustrating a driver circuitdevice according to a conventional embodiment. As shown, the drivercircuit 201 can be similar to the driver circuit of FIG. 1A with acenter-tapped termination. As an example, this driver circuit 201represents a driver module for a signal pull up with “0” to “1”transition. The indicator 251 shows that this driver module isconfigured for the pull-up signal from “0” to “1”. This pull-up driveris configured with a stronger Ron, resistance coefficient, as shown bythe pull-up resistance network 211 within the driver 110. As an example,the resistance network can include a plurality of resistors connected inparallel between VDD and the driver output. Those of ordinary skill inthe art will recognize other variations, modifications, andalternatives.

FIG. 2B is a simplified circuit diagram illustrating a driver circuitdevice according to a conventional embodiment. As shown, the drivercircuit 202 can be a similar to the center-tapped terminated drivercircuit of FIG. 1A. As an example, this driver circuit 202 represents adriver module for a signal pull-up with consecutive “1”s. The indicator252 shows that this driver module is configured for the pull-up signalfor consecutive “1”s. This pull-up driver is configured with a weakerRon, resistance coefficient, as shown by the pull-up resistance network212 within the driver 110. As an example, this resistance network can bea reduced network compared to the network 211 of FIG. 2A.

FIG. 2C is a simplified circuit diagram illustrating a driver circuitdevice according to a conventional embodiment. As shown, the drivercircuit 203 can be a similar to the center-tapped terminated drivercircuit of FIG. 1A. As an example, this driver circuit 203 represents adriver module for a signal pull-down. The indicator 253 shows that thisdriver module is configured for the pull-down signal from “1” to “0”.Similar to the driver module of FIG. 2A, this pull-down driver isconfigured with a stronger Ron, resistance coefficient, as shown by thepull-up resistance network 213 within the driver 110. As an example, theresistance network can include a plurality of resistors connected inparallel between the driver output and GND.

FIG. 2D is a simplified circuit diagram illustrating a driver circuitdevice according to a conventional embodiment. As shown, the drivercircuit 204 can be a similar to the center-tapped terminated drivercircuit of FIG. 1A. As an example, this driver circuit 204 represents adriver module for a signal pull-down with consecutive “0”s. Theindicator 254 shows that this driver module is configured for thepull-down signal for consecutive “0”s. This pull-down driver isconfigured with a weaker Ron, resistance coefficient, as shown by thepull-up resistance network 214 within the driver 110. As an example,this resistance network can be a reduced network compared to the network213 of FIG. 2C. These circuits are simplified representations each witha 1-tap pre-emphasis. Multiple taps with different coefficients can beimplemented in a system or device as well.

FIG. 3A is a simplified circuit diagram illustrating a driver circuitdevice according to an embodiment of the present invention. As shown,the driver circuit 301 can be similar to the driver circuit of FIG. 1Bwith a power termination. As an example, this driver circuit 301represents a driver module for a signal pull-up with “0” to “1”transition, denoted by indicator 351. Compared to the driver circuit ofFIG. 2A, this pull-up driver is configured with a weaker Ron, resistancecoefficient, as shown by the pull-up resistance network 311 within thedriver 110. To have a stronger pull-up signal with VDD termination, aweaker pull-up Ron is needed (de-emphasis). Those of ordinary skill inthe art will recognize other variations, modifications, andalternatives.

FIG. 3B is a simplified circuit diagram illustrating a driver circuitdevice according to an embodiment of the present invention. As shown,the driver circuit 302 can be similar to the driver circuit to the powerterminated driver circuit of FIG. 1B. As an example, this driver circuit302 represents a driver module for a signal pull-up with consecutive“1”s, denoted by indicator 352. Compared to the driver circuit of FIG.2B, this pull-up driver is configured with a stronger Ron, resistancecoefficient, as shown by the pull-up resistance network 312 within thedriver 110. The configuration of the resistance networks 311 and 312 arethe inverse of the configuration of the resistance networks 211 and 212of FIGS. 2A and 2B, respectively.

FIG. 3C is a simplified circuit diagram illustrating a driver circuitdevice according to an embodiment of the present invention. As shown,the driver circuit 303 can be similar to the driver circuit to the powerterminated driver circuit of FIG. 1B. As an example, this driver circuit303 represents a driver module for a signal pull-down from “1” to “0”,denoted by indicator 353. Similar to FIG. 2C, this driver circuit isalso configured with a stronger Ron, resistance coefficient, as shown bythe pull-up resistance network 313 within the driver 110.

FIG. 3D is a simplified circuit diagram illustrating a driver circuitdevice according to an embodiment of the present invention. As shown,the driver circuit 304 can be similar to the driver circuit to the powerterminated driver circuit of FIG. 1B. As an example, this driver circuit304 represents a driver module for a signal pull-down for consecutive“0”s, denoted by indicator 354. Similar to FIG. 2D, this driver circuitis also configured with a weaker Ron, resistance coefficient, as shownby the pull-up resistance network 314 within the driver 110. Theconfiguration of the resistance networks 313 and 314 are the same as theconfiguration of the resistance networks 213 and 214 of FIGS. 2C and 2D,respectively.

In an embodiment, the present invention provides a driver circuit devicewith power terminations using driver equalization. The driver caninclude a first driver module which includes a first driver having afirst driver output, wherein the first driver is configured with a firstresistance module, the first resistance module being characterized by aweak on-resistance, a first transmission line channel having a first endand a second end, the first end of the first transmission line channelbeing coupled to the first driver output, a first receiver having afirst receiver input, the second end of the first transmission linechannel being coupled to the first receiver input; and a first powertermination coupled to the first receiver input and the second end ofthe first transmission line channel. The first driver module isconfigured for a pull-up signal from a “0” value to a “1” value, whereinthe first driver is configured to pre-emphasize a pull-up signal fordriver equalization. The weak on-resistance is characterized by aresistance value greater than or equal to 50Ω.

In a specific embodiment, the driver circuit device can include a seconddriver module including a second driver having a second driver output,wherein the second driver is configured with a second resistance module,the second resistance module being characterized by a strongon-resistance, a second transmission line channel having a first end anda second end, the first end of the second transmission line channelbeing coupled to the second driver output, a second receiver having asecond receiver input, the second end of the second transmission linechannel being coupled to the second receiver input; and a second powertermination coupled to the second receiver input and the second end ofthe second transmission line channel. The second driver module isconfigured for a pull-up signal of consecutive “1” values. The strongon-resistance is characterized by a resistance value ranging between 0Ωto 50Ω.

In an example, pull-down Ron with VDD termination has no change from theconfiguration for the center-tapped termination. As describedpreviously, the pull-up Ron with VDD termination is configured to beweaker in order to have a stronger pull-up signal. For a GND terminatedconfiguration, a weaker pull-down Ron (de-emphasis) is needed to have astronger pull-down signal.

In other words, a weaker pull-up driver is needed to pre-emphasize thepull-up signal for driver equalization in power terminated transmissionline channels and a weaker pull-down driver is needed to pre-emphasizethe pull-down signal for driver equalization in ground terminatedtransmission line channels. In the transmission line channels with powerterminations, a weaker pull-up Ron is implemented. In the transmissionline channels with ground terminations, a weaker pull-down Ron isimplemented. Of course, there can be other variations, modifications,and alternatives.

In an embodiment, the present invention provides a driver circuit devicewith ground terminations using driver equalization. The driver circuitdevice can include a first driver module including a first driver havinga first driver output, wherein the first driver is configured with afirst resistance module, the first resistance module being characterizedby a weak on-resistance, a first transmission line channel having afirst end and a second end, the first end of the first transmission linechannel being coupled to the first driver output, a first receiverhaving a first receiver input, the second end of the first transmissionline channel being coupled to the first receiver input; and a firstground termination coupled to the first receiver input and the secondend of the first transmission line channel. The first driver module isconfigured for a pull-down signal from a “1” value to a “0” value,wherein the first driver is configured to pre-emphasize a pull-downsignal for driver equalization. The first driver module is configuredfor a pull-down signal from a “1” value to a “0” value. The weakon-resistance is characterized by a resistance value greater than orequal to 50Ω.

In a specific embodiment, the driver circuit device can include a seconddriver module including a second driver having a second driver output,wherein the second driver is configured with a second resistance module,the second resistance module being characterized by a strongon-resistance, a second transmission line channel having a first end anda second end, the first end of the second transmission line channelbeing coupled to the second driver output, a second receiver having asecond receiver input, the second end of the second transmission linechannel being coupled to the second receiver input; and a second groundtermination coupled to the second receiver input and the second end ofthe second transmission line channel. The second driver module isconfigured for a pull-down signal of consecutive “0” values, wherein thefirst driver is configured to pre-emphasize a pull-down signal fordriver equalization. The strong on-resistance is characterized by aresistance value ranging between 0Ω to 50Ω.

FIG. 4 is a simplified graph illustrating an impulse response at areceiver input of a driver circuit device according to an embodiment ofthe present invention. This graph 400 shows multiple plots of impulseresponses according to varying on-resistances (Ron) in the case ofpull-up de-emphasis with VDD termination. As shown, signal impulse isstronger as Ron is weaker.

FIG. 5A is a simplified graph illustrating an eye diagram of a drivercircuit device according to a conventional embodiment. This graph 501shows an eye diagram at the receiver input of a driver circuit devicewithout emphasis, such as with the conventional embodiment of FIGS. 2Athrough 2D.

FIG. 5B is a simplified graph illustrating an eye diagram of a drivercircuit device according to an embodiment of the present invention. Thisgraph 502 shows an eye diagram at the receiver input of a driver circuitdevice with pull-up (PU) de-emphasis and pull-down (PD) pre-emphasis. Anexample of the pull-up de-emphasis was shown in FIGS. 3A and 3B.Compared to the graph of FIG. 5A, the pull-up de-emphasis and pull-downpre-emphasis produced an 80 mV center eye improvement.

FIG. 6A is a simplified graph illustrating a signal output for a drivercircuit device according to an embodiment of the present invention. Asshown, graph 601 shows drive current (Idrv), drive voltage (Vdrv), andoutput voltage (Vo) over time across a transmission line channel with animpedance (Zo) with an on-resistance value of 50 (Z-matched line).Considering an example driver with an NMOS and a PMOS, this graph beginswith the NMOS turned on and the PMOS turned off. As the NMOS is turnedoff and the PMOS is turned on, Idrv drops to 0 and Vdrv snaps instantlyto full VDD (1.2V in this case). Vo also snaps to full VDD after adelay. In an example, the NMOS turning off interrupts the steady stateof current Idrv=VDD/(RT+RN) causing a reverse current wave I− into thetransmission line with an associated voltage wave V−=Zo*I− (V ispositive due to −z propagation). Max V+=Zo*Idrv.

FIG. 6B is a simplified graph illustrating a signal output for a drivercircuit device according to an embodiment of the present invention. Asshown, graph 602 shows drive voltage and output voltage over time withan on-resistance value of 25. Considering again an example driver withan NMOS and a PMOS, this graph begins with the NMOS turned on and thePMOS turned off. As the NMOS is turned off and the PMOS is turned on,Idrv drops to 4 mA and Vdrv snaps instantly to 1.4. Vo snaps to full VDDafter a delay similar to the case in graph 601. Idrv drops to 0 afteranother delay, and Vout drops to Vdd. In an example, this effect ismaximized with high-Z PMOS. A “strong” PMOS fights this pulse bybleeding Idrv, which actually creates a weaker drive (4 mA@250 ps). Theenergized transmission lines are the actual pull-up device, rather thanthe PMOS transistor itself. The same theory can be applied to pull downsignals with GND terminations.

FIG. 7 is a simplified circuit diagram illustrating a driver circuitdevice according to an embodiment of the present invention. As shown,the circuit diagram 700 includes driver with a PMOS 710 and an NMOS 720coupled to a transmission line channel (Zo). This diagram is related tothe graphs shown in FIGS. 6A and 6B. Vdrv is shown at the input to thedriver on the left, which is also electrically coupled to thetransmission line channel 730. Vout at the other end of the channel 730is terminated to VDD (1.2V). Idrv is shown bleeding towards the driver,which contributes to the weaker drive described previously.

While the above is a full description of the specific embodiments,various modifications, alternative constructions and equivalents may beused. Therefore, the above description and illustrations should not betaken as limiting the scope of the present invention which is defined bythe appended claims.

What is claimed is:
 1. A method of driver equalization in a transmissionline of a driver circuit device, the method comprising: providing thedriver circuit device, the driver circuit device having a firstpower-terminated driver module, the first power-terminated driver moduleincluding a first driver having a first driver output, a firsttransmission line channel having a first end and a second end, the firstend of the first transmission line channel being coupled to the firstdriver output, a first receiver having a first receiver input, thesecond end of the first transmission line channel being coupled to thefirst receiver input, and a first power termination coupled to the firstreceiver input and the second end of the first transmission linechannel; configuring the first driver with a first resistance networkmodule, the first resistance network module being characterized by aweak on-resistance; receiving, by the first power-terminated drivermodule, a pull-up signal; and pre-emphasizing, by the first resistancenetwork module of the first driver, the pull-up signal to strengthen thepull-up signal for driver equalization.
 2. The method of claim 1 whereinthe first driver module is configured for a pull-up signal from a “0”value to a “1” value.
 3. The method of claim 1 wherein the weakon-resistance is characterized by a resistance value greater than orequal to 50Ω.
 4. The method of claim 1 wherein the driver circuit devicefurther comprises: a second power-terminated driver module including asecond driver having a second driver output, a second transmission linechannel having a first end and a second end, the first end of the secondtransmission line channel being coupled to the second driver output, asecond receiver having a second receiver input, the second end of thesecond transmission line channel being coupled to the second receiverinput, and a second power termination coupled to the second receiverinput and the second end of the second transmission line channel; andfurther comprising configuring the second driver with a secondresistance network module, the second resistance network module beingcharacterized by a strong on-resistance; receiving, by the secondpower-terminated driver module, the pull-up signal; and deemphasizing,by the second resistance network module of the second driver, thepull-up signal to weaken the pull-up signal for driver equalization. 5.The method of claim 4 wherein the second power-terminated driver moduleis configured for a pull-up signal of consecutive “1” values.
 6. Themethod of claim 4 wherein the strong on-resistance is characterized by aresistance value ranging between 0Ω to 50Ω.
 7. A method of driverequalization in a transmission line of a driver circuit device, themethod comprising: providing the driver circuit device, the drivercircuit device having a first ground-terminated driver module, the firstground-terminated driver module including a first driver having a firstdriver output, a first transmission line channel having a first end anda second end, the first end of the first transmission line channel beingcoupled to the first driver output, a first receiver having a firstreceiver input, the second end of the first transmission line channelbeing coupled to the first receiver input, and a first groundtermination coupled to the first receiver input and the second end ofthe first transmission line channel; configuring the first driver with afirst resistance network module, the first resistance network modulebeing characterized by a weak on-resistance; receiving, by the firstground-terminated driver module, a pull-down signal; andpre-emphasizing, by the first resistance network module of the firstdriver, the pull-down signal to strengthen the pull-down signal fordriver equalization.
 8. The method of claim 7 wherein the firstground-terminated driver module is configured for a pull-down signalfrom a “1” value to a “0” value.
 9. The method of claim 7 wherein theweak on-resistance is characterized by a resistance value greater thanor equal to 50Ω.
 10. The method of claim 1 wherein the driver circuitdevice further comprises: a second ground-terminated driver moduleincluding a second driver having a second driver output, a secondtransmission line channel having a first end and a second end, the firstend of the second transmission line channel being coupled to the seconddriver output, a second receiver having a second receiver input, thesecond end of the second transmission line channel being coupled to thesecond receiver input, and a second ground termination coupled to thesecond receiver input and the second end of the second transmission linechannel; and further comprising configuring the second driver with asecond resistance network module, the second resistance network modulebeing characterized by a strong on-resistance; receiving, by the secondground-terminated driver module, the pull-down signal; anddeemphasizing, by the second resistance network module of the seconddriver, the pull-down signal to weaken the pull-down signal for driverequalization.
 11. The method of claim 10 wherein the secondpower-terminated driver module is configured for a pull-down signal ofconsecutive “0” values.
 12. The method of claim 10 wherein the strongon-resistance is characterized by a resistance value ranging between 0Ωto 50Ω.
 13. A power-terminated driver circuit device, the devicecomprising: a first driver coupled to a first end of a firsttransmission line, the first driver being configured with a firstresistance network characterized by a weak on-resistance for a pull-upsignal with “0”-to-“1” transition; a first power termination coupled toa second end of the first transmission line; a second driver coupled toa first end of a second transmission line, the second driver beingconfigured with a second resistance network characterized by a strongon-resistance for a pull-up signal with consecutive “1”s; a second powertermination coupled to a second end of the second transmission line; athird driver coupled to a first end of a third transmission line, thethird driver being configured with a third resistance networkcharacterized by a strong on-resistance for a pull-down signal with“1”-to-“0” transition; a third power termination coupled to a second endof the third transmission line; a fourth driver coupled to a fourthtransmission line, the fourth driver being configured with a fourthresistance network characterized by a weak on-resistance for a pull-downsignal with consecutive “0”s; and a fourth power-termination coupled toa second end of the fourth transmission line; wherein thepower-terminated driver circuit device is configured with pull-upde-emphasis and pull-down pre-emphasis for driver equalization.
 14. Thedevice of claim 13 wherein each of the weak on-resistances ischaracterized by a resistance value greater than or equal to 50Ω. 15.The device of claim 13 wherein each of the strong on-resistances ischaracterized by a resistance value ranging between 0Ω to 50Ω.
 16. Thedevice of claim 13 wherein the first and second transmission lines areconfigured as signal pull-up devices when in energized states.
 17. Aground-terminated driver circuit device, the device comprising: a firstdriver coupled to a first end of a first transmission line, the firstdriver being configured with a first resistance network characterized bya strong on-resistance for a pull-up signal with “0”-to-“1” transition;a first ground termination coupled to a second end of the firsttransmission line; a second driver coupled to a first end of a secondtransmission line, the second driver being configured with a secondresistance network characterized by a weak on-resistance for a pull-upsignal with consecutive “1”s; a second ground termination coupled to asecond end of the second transmission line; a third driver coupled to afirst end of a third transmission line, the third driver beingconfigured with a third resistance network characterized by a weakon-resistance for a pull-down signal with “1”-to-“0” transition; a thirdground termination coupled to a second end of the third transmissionline; a fourth driver coupled to a fourth transmission line, the fourthdriver being configured with a fourth resistance network characterizedby a strong on-resistance for a pull-down signal with consecutive “0”s;and a fourth ground termination coupled to a second end of the fourthtransmission line; wherein the ground-terminated driver circuit deviceis configured with pull-up pre-emphasis and pull-down de-emphasis fordriver equalization.
 18. The device of claim 17 wherein each of the weakon-resistances is characterized by a resistance value greater than orequal to 50Ω.
 19. The device of claim 17 wherein each of the strongon-resistances is characterized by a resistance value ranging between 0Ωto 50Ω.
 20. The device of claim 17 wherein the third and fourthtransmission lines are configured as signal pull-down devices when inenergized states.